15 Mar
2007
15 Mar
'07
12:43 a.m.
On Tue, 13 Mar 2007, Roger Holmes wrote:
Good. Yesterday evening I completed the
hardware setup
for applying pulses to the interrupt circuitry. Time
of the pulse is adjustable to 5-20us after the reset.
So there is time for the program to enable interrupts
and the whole process fits into the memory of my
logic analyzer. So I will hunt for the interrupts on
saturday...
Regarding the devices (timer for example) you wrote:
Actually I was employed a junior programmer and
eventually became
responsible for the Coral 66 compiler and utility software for the
920. Later on I became a 'Senior Systems Engineer' and made some
suggestions to the engineers here and there. I really learned about
hardware as a hobby with my ICT1301 mainframe. After I left I
Awesome machine! It is really a huge project to
bring this one up and keep it running! I surfed
around in the links you mentioned in your posting
and was REALLY IMPRESSED!
One of the best sounds I ever heared is the spinning
up of the drum ;-)
64k of data to wide format Versatec Plotters at a
million BYTES a
second without any intervention from the CPU (i.e. by Direct Memory
Access). While that was going on the CPU was imaging the next chunk
of data to be sent. It had to be real time because if the plotter ran
out of data it would stop and the liquid toner would soak into the
paper and spoil the image.
Yes, this is a challenging task. Compared to this,
the modern Multi-GHz computers perform very bad.
from location zero and the B from location 1.
That is a clever concept and should be easy to detect.
So I will have to do some hardware work in supplying the
signals to the appropriate lines and than I will be
able to test this hypothesis. things like compasses, gyros, special digital radio
receivers and
transmitters, custom keyboards and vector and raster monitors, chart
recorders and much more.
Did the vector monitors have own intelligence like
terminals, or did you send x- and y- values to them?
Honestly speaking this is an upcoming project for
my PEC, too. I already got a HP1335a analog storage
vector display and I want to connect it to the
unit via two DACs. This would give me a writing speed
of approximately 20000 pixels per second via the
serial links. Not very fast, but OK.
A chap who used to be a service engineer on my
computer many years
ago contacted a while back and kindly agreed to help me bring my
computer back into a useable state. He has a web site describing the
project, and there are some pictures of him and my machine at http://
ict1301.co.uk/13010510.htm . The rotary switches can be used to put
data into registers, including the three instruction registers, so
you can enter programs from the keys if all else fails. The green
squares have four indicators in each one, so can display one decimal
digit (it is primarily a decimal machine, 12 digits * 4 bits)
That is really a
great piece of history and
it is of course beeing worth beeing taken
care of! How often do you turn this baby
on?
According to the internet this is made of germanium
transistors. What type of transistors do you use
if you have to replace them?
What are the major (technical) problems you enounter
apart from corrosion of contacts? Do you encounter
semiconductor failures often?
Oh for all that space! I have two machines in less
space they use for
one. Mind you one of mine is not assembled. It makes taking pictures
very difficult.
Yes of course. You'd need a 80m^2 exhibition
area for one of these babies to make photos like
this...
Keep on the excellent work on the mainframe,
thanks again,
Erik.